[PATCH 13/39] megaraid: simplify internal command handling

Christoph Hellwig
2014-03-17T13:27:46Z

[-- Attachment #1: 0013-megaraid-simplify-internal-command-handling.patch --]
[-- Type: text/plain, Size: 9739 bytes --]

We don't use the passed in scsi command for anything, so just add a adapter-
wide internal status to go along with the internal scb that is used unter
int_mtx to pass back the return value and get rid of all the complexities
and abuse of the scsi_cmnd structure.

This gets rid of the only user of scsi_allocate_command/scsi_free_command,
which can now be removed.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Cc: Sumit.Saxena@lsi.com
Cc: kashyap.desai@lsi.com
Cc: megaraidlinux@lsi.com
---
drivers/scsi/megaraid.c | 120 ++++++++++++----------------------------------
drivers/scsi/megaraid.h | 3 +-
drivers/scsi/scsi.c | 56 ----------------------
include/scsi/scsi_cmnd.h | 3 --
4 files changed, 32 insertions(+), 150 deletions(-)

diff --git a/drivers/scsi/megaraid.c b/drivers/scsi/megaraid.c
index 816db12..8bca30f 100644
--- a/drivers/scsi/megaraid.c
+++ b/drivers/scsi/megaraid.c
@@ -531,13 +531,6 @@ mega_build_cmd(adapter_t *adapter, Scsi_Cmnd *cmd, int *busy)
int target = 0;
int ldrv_num = 0; /* logical drive number */

-
- /*
- * filter the internal and ioctl commands
- */
- if((cmd->cmnd[0] == MEGA_INTERNAL_CMD))
- return (scb_t *)cmd->host_scribble;
-
/*
* We know what channels our logical drives are on - mega_find_card()
*/
@@ -1439,19 +1432,22 @@ mega_cmd_done(adapter_t *adapter, u8 completed[], int nstatus, int status)

cmdid = completed[i];

- if( cmdid == CMDID_INT_CMDS ) { /* internal command */
+ /*
+ * Only free SCBs for the commands coming down from the
+ * mid-layer, not for which were issued internally
+ *
+ * For internal command, restore the status returned by the
+ * firmware so that user can interpret it.
+ */
+ if (cmdid == CMDID_INT_CMDS) {
scb = &adapter->int_scb;
- cmd = scb->cmd;
- mbox = (mbox_t *)scb->raw_mbox;

- /*
- * Internal command interface do not fire the extended
- * passthru or 64-bit passthru
- */
- pthru = scb->pthru;
+ list_del_init(&scb->list);
+ scb->state = SCB_FREE;

- }
- else {
+ adapter->int_status = status;
+ complete(&adapter->int_waitq);
+ } else {
scb = &adapter->scb_list[cmdid];

/*
@@ -1640,25 +1636,7 @@ mega_cmd_done(adapter_t *adapter, u8 completed[], int nstatus, int status)
cmd->result |= (DID_BAD_TARGET << 16)|status;
}

- /*
- * Only free SCBs for the commands coming down from the
- * mid-layer, not for which were issued internally
- *
- * For internal command, restore the status returned by the
- * firmware so that user can interpret it.
- */
- if( cmdid == CMDID_INT_CMDS ) { /* internal command */
- cmd->result = status;
-
- /*
- * Remove the internal command from the pending list
- */
- list_del_init(&scb->list);
- scb->state = SCB_FREE;
- }
- else {
- mega_free_scb(adapter, scb);
- }
+ mega_free_scb(adapter, scb);

/* Add Scsi_Command to end of completed queue */
list_add_tail(SCSI_LIST(cmd), &adapter->completed_list);
@@ -4133,23 +4111,15 @@ mega_internal_dev_inquiry(adapter_t *adapter, u8 ch, u8 tgt,
* The last argument is the address of the passthru structure if the command
* to be fired is a passthru command
*
- * lockscope specifies whether the caller has already acquired the lock. Of
- * course, the caller must know which lock we are talking about.
- *
* Note: parameter 'pthru' is null for non-passthru commands.
*/
static int
mega_internal_command(adapter_t *adapter, megacmd_t *mc, mega_passthru *pthru)
{
- Scsi_Cmnd *scmd;
- struct scsi_device *sdev;
+ unsigned long flags;
scb_t *scb;
int rval;

- scmd = scsi_allocate_command(GFP_KERNEL);
- if (!scmd)
- return -ENOMEM;
-
/*
* The internal commands share one command id and hence are
* serialized. This is so because we want to reserve maximum number of
@@ -4160,73 +4130,45 @@ mega_internal_command(adapter_t *adapter, megacmd_t *mc, mega_passthru *pthru)
scb = &adapter->int_scb;
memset(scb, 0, sizeof(scb_t));

- sdev = kzalloc(sizeof(struct scsi_device), GFP_KERNEL);
- scmd->device = sdev;
-
- memset(adapter->int_cdb, 0, sizeof(adapter->int_cdb));
- scmd->cmnd = adapter->int_cdb;
- scmd->device->host = adapter->host;
- scmd->host_scribble = (void *)scb;
- scmd->cmnd[0] = MEGA_INTERNAL_CMD;
-
- scb->state |= SCB_ACTIVE;
- scb->cmd = scmd;
+ scb->idx = CMDID_INT_CMDS;
+ scb->state |= SCB_ACTIVE | SCB_PENDQ;

memcpy(scb->raw_mbox, mc, sizeof(megacmd_t));

/*
* Is it a passthru command
*/
- if( mc->cmd == MEGA_MBOXCMD_PASSTHRU ) {
-
+ if (mc->cmd == MEGA_MBOXCMD_PASSTHRU)
scb->pthru = pthru;
- }
-
- scb->idx = CMDID_INT_CMDS;

- megaraid_queue_lck(scmd, mega_internal_done);
+ spin_lock_irqsave(&adapter->lock, flags);
+ list_add_tail(&scb->list, &adapter->pending_list);
+ /*
+ * Check if the HBA is in quiescent state, e.g., during a
+ * delete logical drive opertion. If it is, don't run
+ * the pending_list.
+ */
+ if (atomic_read(&adapter->quiescent) == 0)
+ mega_runpendq(adapter);
+ spin_unlock_irqrestore(&adapter->lock, flags);

wait_for_completion(&adapter->int_waitq);

- rval = scmd->result;
- mc->status = scmd->result;
- kfree(sdev);
+ mc->status = rval = adapter->int_status;

/*
* Print a debug message for all failed commands. Applications can use
* this information.
*/
- if( scmd->result && trace_level ) {
+ if( rval && trace_level ) {
printk("megaraid: cmd [%x, %x, %x] status:[%x]\n",
- mc->cmd, mc->opcode, mc->subopcode, scmd->result);
+ mc->cmd, mc->opcode, mc->subopcode, rval);
}

mutex_unlock(&adapter->int_mtx);
-
- scsi_free_command(GFP_KERNEL, scmd);
-
return rval;
}

-
-/**
- * mega_internal_done()
- * @scmd - internal scsi command
- *
- * Callback routine for internal commands.
- */
-static void
-mega_internal_done(Scsi_Cmnd *scmd)
-{
- adapter_t *adapter;
-
- adapter = (adapter_t *)scmd->device->host->hostdata;
-
- complete(&adapter->int_waitq);
-
-}
-
-
static struct scsi_host_template megaraid_template = {
.module = THIS_MODULE,
.name = "MegaRAID",
diff --git a/drivers/scsi/megaraid.h b/drivers/scsi/megaraid.h
index 4d0ce4e..8f2e026 100644
--- a/drivers/scsi/megaraid.h
+++ b/drivers/scsi/megaraid.h
@@ -853,10 +853,10 @@ typedef struct {

u8 sglen; /* f/w supported scatter-gather list length */

- unsigned char int_cdb[MAX_COMMAND_SIZE];
scb_t int_scb;
struct mutex int_mtx; /* To synchronize the internal
commands */
+ int int_status; /* status of internal cmd */
struct completion int_waitq; /* wait queue for internal
cmds */

@@ -1004,7 +1004,6 @@ static int mega_del_logdrv(adapter_t *, int);
static int mega_do_del_logdrv(adapter_t *, int);
static void mega_get_max_sgl(adapter_t *);
static int mega_internal_command(adapter_t *, megacmd_t *, mega_passthru *);
-static void mega_internal_done(Scsi_Cmnd *);
static int mega_support_cluster(adapter_t *);
#endif

diff --git a/drivers/scsi/scsi.c b/drivers/scsi/scsi.c
index 2b12983..8b2bc06 100644
--- a/drivers/scsi/scsi.c
+++ b/drivers/scsi/scsi.c
@@ -403,62 +403,6 @@ static void scsi_put_host_cmd_pool(gfp_t gfp_mask)
}

/**
- * scsi_allocate_command - get a fully allocated SCSI command
- * @gfp_mask: allocation mask
- *
- * This function is for use outside of the normal host based pools.
- * It allocates the relevant command and takes an additional reference
- * on the pool it used. This function *must* be paired with
- * scsi_free_command which also has the identical mask, otherwise the
- * free pool counts will eventually go wrong and you'll trigger a bug.
- *
- * This function should *only* be used by drivers that need a static
- * command allocation at start of day for internal functions.
- */
-struct scsi_cmnd *scsi_allocate_command(gfp_t gfp_mask)
-{
- struct scsi_host_cmd_pool *pool = scsi_get_host_cmd_pool(gfp_mask);
-
- if (!pool)
- return NULL;
-
- return scsi_pool_alloc_command(pool, gfp_mask);
-}
-EXPORT_SYMBOL(scsi_allocate_command);
-
-/**
- * scsi_free_command - free a command allocated by scsi_allocate_command
- * @gfp_mask: mask used in the original allocation
- * @cmd: command to free
- *
- * Note: using the original allocation mask is vital because that's
- * what determines which command pool we use to free the command. Any
- * mismatch will cause the system to BUG eventually.
- */
-void scsi_free_command(gfp_t gfp_mask, struct scsi_cmnd *cmd)
-{
- struct scsi_host_cmd_pool *pool = scsi_get_host_cmd_pool(gfp_mask);
-
- /*
- * this could trigger if the mask to scsi_allocate_command
- * doesn't match this mask. Otherwise we're guaranteed that this
- * succeeds because scsi_allocate_command must have taken a reference
- * on the pool
- */
- BUG_ON(!pool);
-
- scsi_pool_free_command(pool, cmd);
- /*
- * scsi_put_host_cmd_pool is called twice; once to release the
- * reference we took above, and once to release the reference
- * originally taken by scsi_allocate_command
- */
- scsi_put_host_cmd_pool(gfp_mask);
- scsi_put_host_cmd_pool(gfp_mask);
-}
-EXPORT_SYMBOL(scsi_free_command);
-
-/**
* scsi_setup_command_freelist - Setup the command freelist for a scsi host.
* @shost: host to allocate the freelist for.
*
diff --git a/include/scsi/scsi_cmnd.h b/include/scsi/scsi_cmnd.h
index 414edf9..dd7c998 100644
--- a/include/scsi/scsi_cmnd.h
+++ b/include/scsi/scsi_cmnd.h
@@ -155,9 +155,6 @@ extern void scsi_release_buffers(struct scsi_cmnd *cmd);
extern int scsi_dma_map(struct scsi_cmnd *cmd);
extern void scsi_dma_unmap(struct scsi_cmnd *cmd);

-struct scsi_cmnd *scsi_allocate_command(gfp_t gfp_mask);
-void scsi_free_command(gfp_t gfp_mask, struct scsi_cmnd *cmd);
-
static inline unsigned scsi_sg_count(struct scsi_cmnd *cmd)
{
return cmd->sdb.table.nents;
--
1.7.10.4